• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Multiplexer Input Voltage


New Member
Greetings Everyone, May i ask does the Vi(Input Voltage) means that the voltage that can be input to the Y0-Y7 or Z is at max 5V ( The Vcc i used is 5V). In my project, the input voltage for the Y0-Y7 is 12V, will that spoil the multiplexer? If so what multiplexer should I use for my project?


Above is the rought schematic i drawn to represent the project i am doing.


Well-Known Member
Most Helpful Member
The voltages on Z and Y0 - Y7 must not be more than the supply voltage, so 12 V will cause damage. If you do apply 12 V, that could cause the 5 V supply voltage to rise as well.

An analogue switch like the 74HC4051 is not good for driving loads like that, as it has quite a large resistance when on, typically 70 Ohms.

I suggest that you use an octal decoder, something like one of these:- https://uk.farnell.com/texas-instruments/cd74hct42e/logic-bcd-decimal-decoder-16dip/dp/3006320 which you can use with seven high-side drivers.


Well-Known Member
Most Helpful Member
You could use an MIC5891

That uses serial data (like SPI, or bit-banging) to select the outputs, but it is intended for a separate output supply and can provide up to half an amp to an output pin.

Any combination of outputs can be switched on, depending on the serial data byte loaded.

The 5801 is similar but switching to ground rather than positive.


New Member
Hi, thanks for the reply, and sorry for the late reply too! After the suggestion and discussion with my mentor, she suggested that I just use multiple MOSFET to act as a switch.

Again, thanks for the help provided by rjenkinsgb and Diver300! Much Appreciated!

Latest threads

EE World Online Articles